Photographic sensitizing dyes and emulsions containing them



United States Patent PHOTOGRAPHIC SENSITIZING DYES AND EMUL- SIONS CONTAINING THEM Leslie G. S. Brooker and Donald W. Heseltine, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Application May 21, 1956 Serial No. 585,946

13 Claims. (Cl. 919-402) This invention relates to certain cyanine :dyes useful in optically sensitizing photographic silver halide emulsions, and to photographic silver halide emulsions sensitized with these cyanine dyes.

The dyes of our invention can advantageously be reprea carbalkoxyl group, such as carbometh'oxyl, carbethoxyl,

etc. (e.g., alower alkoxy carbonyl group), and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from-5 (n is 1') to 6 (n is 2) atoms in the heterocyclic ring, such as those selected from the group consisting of those of the thiazole series (e.g., thiazole, 4-methylthiazole, S-methylthiazole, 4-phenylthiazole, 5-phenylthiazole,. 4,5-dimethylthiazole, 4,5 diphenylthiazole, 4-(2-thienyl)thiazole, etc.), those of the benzothiazole series (e.g., benzothiazole, 4-methylbenzothiazol e, 5-methylbenzothiazo1e,. G-methylbenzothiazole, 4-phenylbenzothiazole, S-phenylbenzothiazole, 4-methoxybenzothiazole, S-methoxybenzothiazole, 6- methoxybenzothiazole, 4-ethoxybenzothiazole, S-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxyhenzothiazole, 5g6-dioxymethylenebenzothiazole, S-hydroxybenzothiazole, 6-hydroxybenzothiazole, etc.), those of the naphthothiazole series (e.g., naphtho[2,1]thiazole, naphthoi 1,2]thiazo1e), S-methoxyna'phthoE 1,2] thiazole, 5 -ethoxynaphtho[ 1,2] thiazole,. 7' methoxynaphtho- [2, 1] thiazole, 8-methoxynaphtho[2,1]thiazole, etc.), those of the thianaphtheno-7',6',4,S-thiazole series (e.g., 4'-methoxythianaphtheno-7,6',4,5 thiazole, etc.), those of the oxazole series (e.g., 4-methyloxazo1e, S-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethy1oxazo1le, 4,5- dimethyloxazole, 5-phenyloxazole, etc.), those of the benzoxazole series (e.g., benzoxazole, S-phenylbenzoxazole, S-methylbenzoxazole, G-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, S-methoxybenzoxazole, 6-methoxybenzoxazol'e, S-ethoxybenzoxazole, S-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.),

formula:

thoseof the naphthoxa-zole series (e.g., naphth[2,1.] oxazole, naphth[1,2]oxazole, etc.), those of the selenazole series. (e.g., 4wmethylselenazole, 4-phenylse1enazole, etc.), those of the benzoselenazole series (e.g., benzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselenazole, etc.) those of the naphthoselenazole series (e.g., naphtho[2,1]selenazole, naphtho[1,2] selenazole, etc.), those of the thiazoline series (e.g., thiaz'oline, 4-methylthiazoline, etc.),. those of. the 2-quinoli-ne series (e.g., quinoline, S-methylquinoline, S-methylquino- 2,882,158 Patented Apr. 14, 1959.

2. line, 7-methy1quinoline, 8-methylq-uinoline, 6'-methoxy.- quinoline, -ethoxyquinoline, G-hydroxyquinoline, 8.-hydroxyquinoline, etc.), those of the 4-quinoline series (e.g., quinoline, 6-methoxyquinoline, 7-methylquinoline, 8- methylquinoline, etc.), those of the l-isoquinoline series (e.g., isoquinoline, 3,4-dihydroisoquinoline, etc.), those of the 3,3-dialky1indolenine series (e.g., 3,3-dimethylindolenine, 3,3,S-trimethylindolenine, 3,3,7-trimethylindolenine, etc.), those of the Z-pyridine series (e.g., pryidine, 3-methylpyridine 4-methylpyridine, S-methylpyridine, 6- rnethylpyridine', 3,4-dimethylpyridine, 3,5-dimethy1pyridine, 3,6-dimethylpyridine, 4,5-dimethylpyridine, 4,6-di methylpyridine, 3-hydroxypyridine, 4-hydroxypyridine', 5"-hydroxypyridine,. G-hydroxypyridine, 3-phenylpyridine, 4-phenylpyridine, 6-phenylpyridine, etc.), those of the 4-pyridine series (e.g., Z-methylpyridine, 3-methylpyridine, 2,3-dimethylpyridine, 2,5-dirnethylpyridine, 2,6'dimethylpyridine, Z-hydroxypyridine, 3-hydroxypyridine, etc.), those of the benzirnidazole series (e.g., benzimidazole, S-chlorobenzimidazole, 5,6-dichlorobenzimidazole, 1,7-trimethylenebenzimidazole, S-acetylbenzirnidazole, 5- ethylcarbamylbenzimidazole, etc.), those of the pyrrolidine series (e.g., pyrrolidine, etc.), those of the acenaphtho[1,2]thiazole series (e.g., acenaphtho[1,2]thiazole, etc.), etc. When Z represents the non-metallic atoms necessary to complete apyrrolidine nucleus, R can represent an aryl group, such as phenyl, tolyl, etc. (e.g., a monocyclic aryl group of. the benzene: series).

Accordingly, it is an object of our invention to provide a new class of optical sensitizing dyes. Another object is to provide photographic silver halide emulsions sensitized with these new dyes. Still another object is to provide methods for making these new dyes. Other objects will become apparent from a consideration of the following description and examples. 7

The instant invention provides methods for making the dyes represented by Formula I above by condensing a cyclammon'ium quaternary salt selected from those represented by the following general formula:

II. Z

wherein R, n and Z each have the values given above, X represents an acid radical, such as chloride, bromide, iodide, thiocyanate, p-t'oluenesullfonate, benzenesulfonate, ethylsulfate, etc, and R represents an alkylmercapto group (e.g., methylmercapto, ethylmercapto, etc.), and arylmercapto group (e.g.,-phenylmercapto, tolylmercapto, etc.), or a fl-acylanilidovinyl group (e.g., B-acetanilidovinyl, B-benzoylanilidovinyl, etc.),, with a compound selected from those represented by the following general formula:

wherein R and Q' have the values given above. A particularly useful group of compounds embraced by Formula III are those represented by the following general Ia.- H

wherein R, R R R R n, d and Z have the values given above.

The condensations of the intermediates of Formula H with the compounds of Formula III (or IIIa) can be accelerated by basic condensing agents, such as the trialkylamines (e.g., triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, etc.), N,N-dialkylanilines (e.g., N,N-d imethylaniline, N,N-diethylaniline, etc.), N-alkylpiperidines (e.g. N-methylpiperidine, N-ethylpiper'idine, etc.), etc. The condensations can be carried outin the presence of an inert diluent, such as the lower alcohols (e.g., ethanol, n-propanol, isopropanol, n-hutanol, etc.), pyridine, quinoline, 1,4-dioxane, etc. Heat accelerates the condensations although temperatures varying from ambient temperature (ca. 25 C.) to the reflux temperature of the reaction mixture can be employed.

The following examples will serve to illustrate more fully the preparation of the dyes of our invention.

Example 1.-2-[ (3-dicyanomethylene-5,5-dimethyl- 1 -cyclohexene-1 -yl)methylene]-3-methylthiaz0lidine 3-methyl-2-thiothiazolidinone (4 g., 1 mol.+200%) and methyl p-toluenesulfonate (7.44 g., 1 mol.|300%) were mixed and gently heated over a free flame and then allowed to cool slowly to room temperature. 3-dicyanomethylene-1,5,S-trimethyl-l-cyclohexene 1.86 g., 1rnol.), triethylamine (5.6 ml., 1 mol.l300%) and pyridine (15 ml.) were then added and the reaction mixture was heated under reflux for ten minutes. The crude dye was precipitated by the addition with stirring of water (100 ml.). The aqueous solution was decanted and the residue boiled with methyl alcohol (50 ml.) and then chilled overnight. The crude product was filtered off and twice recrystallized from ethyl alcohol. The yield of purified dye was 1.28 g. (46%), M.P. 16l-2 C.

Example 2.--2-[(S-dicyanomethylene-5,5dimethyl-1- cyclohexen-I -yl) -methylene] -3-methylbenzoxazoline 2-methylmercaptobenzoxazole (4.95 g., 1 mol.+200%) and methyl p-toluenesulfonate (5.6 g., 1 mol.+200%) were mixed and heated to reflux over a free flame and then allowed to cool slowly to room temperature. 3-.dicyanomethylene-1,5,S-trimethyl-l-cyclohexene (1.86 g., 1 mol.), triethylamine 4.2 ml., 1 mo1.+2 0%) and Py dine (15 ml.) were added and the reaction mixture heated under reflux for ten minutes. The crude dye was precipitated by the addition with stirring of methyl alcohol ml.). After chilling overnight, the crude dye was filtered 01f, washed with methyl alcohol and dried. After two recrystallizations from pyridine and methyl alcohol, the yield of pure dye was 2.16 g., (68% M.P. 1689 C.

Example 3.2-[ (3-dic yan0methylene 5,5 dimethyl-I- cyclohexen-I-yl) -met hylene] -3-methylbenz0thiaz0line Example 4.2-[(3-dicyan0methylene 5,5 dimethyl-I- cyclohexen-I -yl) -methylene] -3-methylbenz0selenaz0line 3-dicyanomethylene 1,5,5 trimethyl 1 cyclohexene (0.93 g., 1 mol.), 3-methyl-2-methylmercaptobenzoselenazolium p-toluenesulfonate (2.07 g., 1 mol.) and triethylamine (1.4 ml., 1 mol.+l00%) were dissolved in pyridine (10 ml.) and heated under reflux for ten minutes. The crude dye was thrown out of solution by the addition with stirring of methyl alcohol (100 ml.). After chilling overnight, the crude dye was filtered oif, washed with methyl alcohol and dried. The yield of purified dye after two recrystallizations from ethyl alcohol was 0.89 g. (47%), M.P. 183-4 C.

Example 5.--2-[(3-dicyan0methylene 5,5 dimethylcyclohexen-I-yl)-methylene] 1 methylnaphtho[1,2] thiazoline 3-dicyanomethylene 1,5,5, trimethyl 1 cyclohexene (0.93 g., 1 mol.), 1-methyl-Z-methylmercaptonaphtho [1,2lthiaz0liurn p-toluenesulfonate (2.09 g., 1 mol.) and triethylarnine (1.4 ml., 1,,mol.+100%) were dissolved in pyridine (15 ml.) and the mixture heated under reflux for ten minutes. The crude dye was thrown out of solution by the addition with stirring of methyl alcohol (100 ml.). After chilling overnight, the crude dye was filtered off, washed with methyl alcohol and dried. The yield of purified dye after three recrystallizations from pyridine and methyl alcohol, was 1.45 g., (77%), M.P. 243-4 C. with dec. Example 6.2-[(3-dicyan0methylene 5,5 dimethyl-I- cyclohexen-I-yl) -methylene] -I-ethyl-1,2-dihydroquino- S-dicyanornethylene 1,5,5 trimethyl 1 cyclohexene (1.86 g., 1 mol.), l-ethyl-2-phenylmercaptoquinolinium p-toluenesulfonate (4.37 g., 1 mol.) and triethylamine (1.4 ml., 1 mol.) were dissolved in pyridine (15 ml.) and heated under reflux for ten minutes. The crude dye was thrown out of solution by the addition with stirring of methyl alcohol (100 ml.). After chilling overnight, the crude dye was filtered off, washed with a little methyl alcohol and dried. The yield of purified dye after two recrystallizations from ethyl alcohol was 1.10 g. (31%), M.P. 2034 C. with dec.

Example 7.--4-[(3-dicyanomethylene 5,5 dimethyl-I- cyclohexen-l -yl) methylene -1-ethyl-1,4-dihydroqainoline Example 8.--2-[(3-dicyanomethylene-5,5-dimethyl-I-cyclohexen-I-yl)-methylene]-1,3-diethylbenzimidazoline 3 dicyanomethylene 1,5,5 trimethyl l cyclohexene (1.86 g., 1 mol.), 1,3-diethyl-2-ethylmercaptobenzimidazolium p-toluenesulfonate (4.06 g., 1 mol.) and triethylamine (2.8 ml., 1 mol.+100%) were dissolved in pyridine (20 m1.) and heated under reflux for ten minutes. The crude dye was thrown out of solution by the addition with stirring of water (100 ml.). The aqueous solution was then decanted and the residue stirred with methyl alcohol until it became crystalline. After chilling overnight, the crude dye was filtered ofli, washed with a little methyl alcohol and dried. After two recrystallizations from ethyl alcohol, the yield of purified dye was 0.39 g., (11%), M.P. 195-6" C. with dec.

Example 9.2- (3-dicyan0methylene-5.5-dimethyI-1-cyclohexen-I -yl methylene] -1 -phenylpyrr0lidine 3 dicyanomethylene 1,5,5 trimethyl 1 cyclohexene (1.86 g., 1 mol.), 2-methylmercapto-l-phenylpyrrolidinium p-toluenesulfonate (3.63 g., 1 mol.) and triethylamine (2.8 ml., 1 mol.+%) were dissolved in pyridine (15 ml.) and heated under reflux for fifteen minutes. The crude product was thrown out of solution by the addition with stirring of water (100 ml.). The aqueous solution was decanted and the residue stirred with methyl alcohol until crystalline, chilled overnight and the crude product filtered off and dried. After two recrystallizations from ethyl alcohol, the yield of purified dye was 0.78 g., (23%), M.P. 224-6 C.

Example ]0.-2- l3-(3-dicyanomethylene-5,5-dimethyl-1- cyclohexen-I -yl) allylidene] -3-ethylbenz0xaz0line HIO CHI O HIC CH: CN

C=CH-OH=CHC =0 C ON N H 41:11:

Example 11.-2-[3-(3-dicyan0methylene-5,5-dimethylcyclohexen-I -yl) allylidene] -3-ethylbenz0thiaz0line HaC\ /CHI 0 3 dicyanomethylene 1,5,5 trimethyl 1 cyclohexene (1.15 g., 1 mol.), Z-fl-acetanilidovinyl-3-ethylbenzothiazolium iodide (4.50 g., 1 mol.) and triethylamine (2.8 ml., 1 mol.+100%) were dissolved in pyridine (15 ml.) and heated under reflux for ten minutes. The

crude dye was thrown out of solution by the addition with stirring of methyl alcohol, the mixture chilled overnight and the crude dye filtered off, washed with methyl alcohol and dried. After two recrystallizations from pyridine and methyl alcohol, the yield of pure dye was 2.61 g. (71%), M.P. 230-1 C. with dec.

Example I2.-2-[(J-dicyanomethylene-S-methyl-I-cyclohexen-1-yl)-methylene]-3-methylbenzoxazoline 3 dicyanomethylene 1,5 dimethyl 1 cyclohexene (0.86 g., 1 mol.), 3-methyl-2-methylmercaptobenzoxazolium p-toluenesulfonate (6.72 g., 1 mol.+l%) and triethylamine (2.8 ml., 1 mol.+300%) were dissolved in pyridine ml.) and heated under reflux for ten minutes. The crude dye was thrown out of solution by the addition with stirring of water (50 ml.). The aqueous solution was decanted and the residue stirred with methyl alcohol until crystalline. After chilling overnight, the crude dye was filtered off, washed with methyl alcohol and dried. After two recrystallizations from pyridine and methyl alcohol, the yield of pure dye was 0.94 g. (62%), M.P. 2523 C. with dec.

Example 13. 2- (3-dicyanomethylene-I -cyclohexen-1- yl) methylene]-3-methylbenzolhiaz0line B-dicyanomethylene-l-methyl-1-cyclohexene (0.79 g., 1 mol.), 3-methyl-2-methylmercaptobenzothiazolium ptoluenesulfonate (3.67 g., l mol.+l00%) and triethylamine 1.4 ml., 1 mol.+l00%) were dissolved in pyridine (10 ml.) and heated under reflux for ten minutes. The crude dye was thrown out of solution by the addition with stirring of water (100 ml.). The aqueous solution was decanted and the residue stirred with methyl alcohol until crystalline. After chilling overnight, the crude dye was filtered off, washed with methyl alcohol and dried. After two recrystallizations from pyridine and methyl alcohol, the yield of pure dye was 0.79 g. (52%), M.P. 256-7" C. with dec.

Example ]4.-2-[ (3 dicyanomethylene -I-cycI0hexen-1- yl) methylene]-3-methylbenzoxazoline This dye was made in 47% yield by the method of the previous example by using 3-methyl-2-methylmercaptobenzoxazolium p-toluenesulfonate in place of the hemthiazolium salt, M.P. 283-5 C. with dec.

Example 15.--2-[3-(3-dicyan0merhyIene-1-cycl0hexen-1- O CN inn,

3-dicyanomethylene-1-methyl-1-cyclohexene (0.79 g., 1 mol.), 2-fi-acetanilidovinyl-3-ethylbenzothiazolium io- Example I6.-2-[ (6 carbethoxy-3-dicyanomethylene-1- cyclohexen-I -yl) methylene] -3-methylbenzoxazoline H1 CaHrO O O C 6-carbethoxy-3-dicyanomethylene 1 methyl-l-cyclohexene (1.15 g., 1 mol.), 3-methyl-Z-methylmercaptobenzoxazolium p-toluenesulfonate (7.02 g., 1 mol. +300%) and triethylamine (2.8 ml., 1 mol.+300%) were dissolved in pyridine (10 ml.) and heated under reflux for ten minutes. The crude dye was then precipitated by the addition of water ml.) and the aqueous solution carefully decanted. The dye failed to crystallize on stirring with methyl alcohol, and was again precipitated with water and then stirred twice with low boiling ligroin. The dye was dissolved in methyl alcohol and chilled for a week with occasional stirring. The crystalline dye was then filtered off and dried. After two crystallizations from methanol, the yield of purified dye was 0.24 g. (13%), M.P. 177-8 C. with dec.

Example I7.2-[(6 carbethoxy-3-dicyanomethylene-I- cyclohexen-I-yl) methylene] -3-methylbenzothiazoline Example 18.2- [3- (6-carbethoxy-3-dicyan0methylene-1- cyclohexen-I -yl) allylidene] -3-ethylbenzoth iazoline CsIL-O O C C CHI N H inn- G-carbethoxy 3 dicyanomethylene-1-methyl-1-cyelohexene (1.15 g., 1 mol.), 2-,8-acetanilidovinyl-3-ethylbenzothiazolium iodide (2.25 g., 1 mol.) and triethylamine (1.4 ml., 1 mol.+l00%) were dissolved in pyridine 10 ml.)and heated under reflux for ten minutes. The crude dye was thrown out of solution by the addition with stirring of water (100 ml.). The aqueous solution was decanted and the residue dissolved in a little methyl alcohol and chilled with occasional stirring for one week. The crude dye was then filtered otf, washed with a little methyl alcohol and dried. After two recrystallizations from pyridine and methyl alcohol, the yield of pure dye was 0.65 g. (swans/ 1 ,185-36 C. with dec..

Example 1,.9.-.2-{ [3- (1 carbethoxy-I -cyanmethylene) 5',5'-dimethyl-1-cyclohexen 1 yl] methyl'ene}-3-methylbenzothiazoline 3-(1 carbethoxy-l-cyanomethylene)-1,5,5-trimethyl-1'- cyclohexene (2.33 g., 1 mol.), 3-methyl-2-methylmercaptobenzothiazoliurn p-toluenesulfonate (4.04 g., 1 mol. and triethylamine (2.8 ml., 1 mol.+100%) were dissolved in pyridine ml.) and heated under reflux for ten minutes. The crude dye was precipitated by the addition with stirring of water (100 ml.). The aqueous solution was decanted and the residue stirred with methyl alcohol until crystalline. After chilling overnight, the crude dye was, filtered off, washed with a little methyl alcohol and dried. After two recrystallizations from ethyl alcohol, the yield of pure dye was 1.12 g. (30%), M.P. 179180 C. with dec.

Example 20.8-[ (S-dicyanomethylene 5,5 dimethyl-I- 9 methyl-8-methylmercaptoacenaptho[1,2]thiazolium p toluenesulfonate (2.2 g., 1 mol.), 3-dicyanomethylene- 1,5,5-trimethyl-l-cyclohexene (0.93 g., 1 mol.) and triethylamine (1.4 ml., 2 mol.+100%) were dissolved in pyridine ml.) and heated under reflux for ten minutes. After chilling, the crude dye was filtered off, washed with Water and methyl alcohol and dried. After two recrystallizations from pyridine and methyl alcohol, the yield of pure dye was 0.7 g., (34%), M.P. 1934 C. with dec.

The intermediates selected from those represented by Formulas III and HM can advantageously be prepared by the method of Widequist (Acta. Chem. Scand., vol. 3:, pp. 3034304, 1949) by condensing a 3-methyl-2-cyclohexen-l-one, with an intermediate of the formula:

LV. ON

R1 wherein R has the values given above. Useful cyclohexeneones include those represented by the following general formula:

(following examples will serve to illustrate the preparafitiolnf of the intermediates of Formula 111 and IIIa.

Example 21 .3-dicyanomethylene 1,5,5 trimetliyl-lcyclohexene HzC CH; H1O CHI )2C=J'J C-CHI Malononitrile (19.8 g., 1 mol.) and isophorone (46 g., 1 mol.+10%) were dissolved in chloroform and ammonium acetate (2.5 g.) and acetic acid (4 ml.) were added. The mixture was then heated under reflux for one hour in a system fitted for continuous removal of water. The chloroform solution was then washed with two ml. portions of water and the chloroform removed by distillation. The residue was then distilled under vacuum yielding 30.2 g. (54%), B.P. -6 C./l9 mm., M.P. 7980 C.

Example 22.-.-3- (1 -carbeth0xy-1-cyano'methylene)1,5,5

trimethyl-I -cyclohexene Ethyl cyanoacetate (34 g., 1 mol.) and isophorene ('46 g., 1 mol.+10%) were dissolved in chloroform and ammonium acetate (2.5 g.) and acetic acid (4 ml.) were added. The reaction mixture was othen heated under reflux for eighteen hours in a system fitted for the continuous removal of water. The chloroform solution was then washed with two 100 ml. portions of water and then the chloroform was removed by distillation. The residue was then distilled under vacuum. The yield of product was 18 g. (26%), B.P. 175-180 C./15 mm.

Example 23.3 dicyanomethylene-l,S-dimethyl-I-cyclohexene H CH:

3,5-dimethyl-2-cyclohexen-l-one (12.4 g., 1 mol.)v and malononitrile (7.3 g., 1 mol.+10%) were dissolved in chloroform and ammonium acetate (2.5 g.) and acetic acid (4 ml) were added. The reaction mixture was then heated under reflux for twenty hours in an apparatus designed for the continuous removal of water. The chloroform solution was then washed with two 20 ml. portions of water and the chloroform removed by distillation. The residue was then distilled under reduced pressure yielding 15.1 g. (87%) of purified product, B.P. l701 75 C./18 mm., M.P. 55-7 C.

Example 24.3-dicyan0methylene 1 methyl-Loyal!)- 3-methyl-2-cyclohexen-l-one (22 g., 1 mol.) and malononitrile (14.5 g., 1 mol.+10%) were dissolved in chloroform (60 ml.) and ammonium acetate (2.5 g.) and acetic acid (4 ml.) were added. The reaction mixture was heated under reflux for four hours in an. apparatus tion, the residue became crystalline. After recrystallization from methyl alcohol, the yield of purified product was 25.5 g. (81%), M.P. 75-6" C.

Example 25.-6- carbethoxy 3 dicyanomethylene-lmethyl-1 -cyclh exene 4-carbethoxy-3-methyl-2-cyclohexen-1-one (18.1 g., 1 mol.) and malononitrile (7.3 g., 1 mol.+10%) were dissolved in chloroform (40 m1.) and ammonium acetate (2.5 g.) and acetic acid (4 ml.) were added. The reaction mixture was then heated under reflux for four hours in an apparatus designed for the continuous removal of water. The chloroform solution was then washed with two 25 ml. portions of water and the chloroform removed by distillation. The residue was then distilled under vacuum yielding 15.6 g. (68%) of product, B.P. 200-201" C./9 mm.

All of the dyes of our invention are particularly useful in manufacturing photographic, silver halide emulsions, serving to alter the sensitivity thereof. Sensitizationby means of our new dyes is, of course, directed primarily to the ordinarily employed, gelatino-silverhalide, developing-out emulsions. The dyes are advantageously incorporated in the washed, finished emulsion and should, of course, be uniformly distributed throughout the emulsion. In the preparation of photographic emulsions containing our'new .dyes, it is only necessary to disperse the dyes in the emulsions. The methods of incorporating dyes in emulsion are simple and well known to those skilled in the art of emulsion making. It is convenient to add the dyes from solutions in appropriate solvents. The solvent must, of course, be compatible with the emulsion and substantially free from any deleterious effect on the light-sensitive materials. Pyridine has proven satisfactory as a solvent for the majority of our new dyes.

The concentration of our new dyes in the emulsion can vary widely, i.e., from about to about 100 mgs. per liter of flowable emulsion. The concentration of the dye will vary according to the type of light-sensiitve material in the emulsion and according to the effects desired. The suitable and most economical concentration for any given emulsion will be apparent to those skilled in the art upon :making the ordinary tests and observations customarily used in the art of emulsion making.

To prepare a gelatino-silver-halide emulsion sensitized with one of our new dyes, the following procedure is satisfactory: A quantity of the dye is dissolved in pyridine or other suitable solvent and a volume of this solution (which may be diluted with methanol) containing from 5 to 100 mgs. of dye is slowly added to about 1000 cc. of a gelatino-silver-halide emulsion, with stirring. Stirring is continued until the dye is uniformly distributed throughout the emulsion. With most of our new dyes, 10 to 20 mgs. of dye per liter of emulsion sufiices to produce the maximum sensitizing effect with the ordinary gelatino-silverbromide (including bromiodide) emulsions. With finegrain emulsions, which include most of the ordinarily employed gelatino-silver-chloride emulsions, somewhat larger concentrations of dye may be necessary to secure .the optimum sensitizing effect.

The above statements are only illustrative and are not to be understood as limiting our invention in any sense, as it will be apparent that our new dyes can be incorporated by other methods in many of the photographic silver halide emulsions customarily'employed in the art. For

- l2 instance, the dyes can be incorporated by bathing a plate or film upon which an emulsion has been coated, in the solution of the dye, in an appropriate solvent. Bathing methods, however, are not to be preferred ordinarily.

Photographic silver halide emulsions which can advantageously be sensitized by means of the new dyes of our invention comprise the customarily employed gelatino-silver-chloride, gelatino-silver-chlorobromide, gelatino-silver-bromide, and gelatino-silver bromiodide developing-out emulsions.

Photographic silver halide emulsions, such as those listed above, containing the sensitizing dyes of our invention can also contain such addenda as chemical sensitizers, e.g., sulfur sensitizers (e.g., allyl thiocarbamide, thiourea, allylisothiocyanate, cystine, etc.), various gold compounds (e.g., potassium chloroaurate, auric trichloride, etc.) (see U.S. Patents 2,540,085; 2,597,856 and 2,597,915), various palladium compounds, such as palladium chloride (U.S. 2,540,086), potassium chloropalladate (U.S. 2,598,079), etc., or mixtures of such sensitizers; anti-foggants, such as ammonium chloroplatinate (U.S. 2,566,245), ammonium chloroplatinite (U.S. 2,566,263), benzotriazole, nitrobenzimidazole, 5-nitroindazole, benzidine, mercaptans, etc. (see Mees, The Theory of the Photographic Process, Macmillan Pub., page 460), or mixtures thereof; hardeners, such as formaldehyde (U.S. 1,763,533), chrome alum (U.S. 1,763,533), glyoxal (U.S. 1,870,354), dibromacrolein (Br. 406,750), etc.; color couplers, such as those described in U.S. Patent 2,423,730, Spence and Carroll U.S. Patent 2,640,776, etc.; or mixtures of such addenda. Dispersing agents for color couplers, such as those set forth in U.S. Patents 2,322,027 and 2,304,940, can also be employed in the above-described emulsions.

In the manner described above, a number of the dyes of our invention represented by Formula I above were separated incorporated in an ordinary gelatino-silverhalide emulsion, the dyes being thoroughly incorporated in the emulsions by stirring. After a short digestion, the emulsions were coated onto ordinary cellulose acetate film supports and the coatings exposed in a spectrograph and sensitiometer, and then developed in the usual way. The type of emulsion (silver-chlorobromide or silver-bromiodide) sensitizing range, and maximum absorption for each of the dyes are indicated in the following table.

Dye of Example Emulsion sensitizing Maximum Range in mu in mu to 570 540 to 610 570 to 650 600 to 650 610 to 650 610 530-690 555 600-725 690 500-590 540 440-540 480 590-695 670 560-750 685 to 585 560 to 630 600 445-595 540 to 620 600 to 630 580 560-770 720 to 630 600 530-650 620 The 2-methylmercapto-l-phenylpyrrolidinium p-toluene sulfonate employed in Example 9 above was prepared as follows: 1-phenyl-2-thiopyrrolidone (1.77 g., 1 mol.) and methyl p-toluene-sulfonate (1.86 g., 1 mol.) were fused and heated on a steam bath for one hour. The solid quaternary salt was used in dye condensations without further purification.

The 1-phenyl-2-thiopyrrolidone used above was prepared as follows: l-phenyl-Z-pyrrolidone (26 g., 1 mol.) [Spath and Lintner Ber., 69B, 2727 (1936)] and phosphorous pentasulfide (18 g., 1 mol. +50%) were dissolved in pyridine ml.) and heated to reflux. After ten minutes the reaction mixture was poured into water 0. .9 i hsti r n -T .e oi y p odu w extracted .wi et and the ethereal solution concentrated and the residue distilled at l95-l9 7 C./ 8 mm. After recrystallization of the solid distillate from ethanol, the yield of pale yellow crystals was 17 g. (59%), MP. 73-5 C.

t The copending application of J. E. Jones Serial No. 586,054, filed on even date herewith (now U.S. Patent 2,860,982, issued November 18, 1958), illustrates wedge spectrograms obtained from photographic silver halide emulsions containing the new dyes of our invention, alone in cornbination with certain pyridine bases.

What we claim as our invention and desire secured by Letters P-atent of the United States is:

r 1;. A photographicsilver halide emulsion sensitized with a, polymethine dye selected from those represented. by the fo lo n ne rmul wherein R represents an alkyl group containing from 1 to 4' carbon atoms, d represents a positive integer of from 1 -to 2, andQ represents the atoms necessary to complete a cyclohexene ring.

2. A photographic silver halide emulsion sensitized with a polymethine dye selected from those represented by the following general formula:

wherein R represents an alkyl group containing from 1 to 4 carbon atoms, d represents a positive integer of from 1 to 2, and Q represents the atoms necessary to complete a cyclohexene ring.

4. A photographic silver halide emulsion sensitized with a polymethine dye selected from those represented by the following general formula:

wherein R represents an alkyl group containing from 1 to 4 carbon atoms, d represents a positive integer of from 1 to 2, and Q represents the atoms necessary to complete a cyclohexene ring.

5,. Aphotographic silver halide emulsion sensitized a polymethine dye selected from those represented by the following general formula:

wherein R represents an alkyl group containing from 1 to 4 carbon atoms, d represents a positive integer of from 1 to 2, and Q represents the atoms necessary to complete a cyclohexene ring.

6. A photographic silver halide emulsion sensitized with a polymethine dye selected from those represented by the following general formula:

/CH2 C wherein R represents an alkyl group containing from 1 to 4 carbon atoms, R represents a member selected from the group consisting of a cyano group and a carbalkoxyl group containing from 2 to 3 carbon atoms, R represents a member selected from the group consisting of a hydrogen atom and a carbalkoxyl group containing from 2 to 3 carbon atoms, R and R each represents a member selected from the group consisting of a hydrogen atom and an alkyl group containing from 1 to 2 carbon atoms, n and d each represents a positive integer of from 1 to 2, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the thiazole series, those of the benzothiazole series, those of the naphthothiazole series, those of the thianaphtheno-7',6',4,5-thiazole series, those of the oxazole series, those of the benzoxazole series, those of the naphthoxazole series, those of the selenazole series, those of the benzoselenazole series, those of the naphthoselenazole series, those of the thiazoline series, those of the 2-quinoline series, those of the 4-quinoline series, those of the l-isoquinoline series, those of the 3,3-dialkylindolenine series, those of the 2-pyridine series, those of the 4-pyridine series, those of the benzimidazole series, those of the pyrrolidine series, and those of the acenaphtho[1,2]thiazole series, provided that when Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the pyrrolidine series, R can additionally represent a monocyclic aryl group of the benzene series.

8. A photographic silver halide emulsion sensitized with 9. A photographic silver halide emulsion sensitized with the polymethine dye represented by the following formula:

10. A photographic silver halide emulsion sensitized with the polymethine dye represented by the formula:

11. A photographic silver halide emulsion sensitized with the polymethine dye represented by the following formula:

Se H

12. A photographic silver halide emulsion sensitized with the polymethine dye represented by the followin formula:

. '1 s 13. A photographic silver halide emulsion sensitized with a polymethine dye selected from those represented by the following general formula:

wherein R represents an alkyl group containing from 1 to 4 carbon atoms, R represents a member selected from the group consisting of a cyano group and an alkoxy carbonyl group containing from 2 to 3 carbon atoms, Q rep resents the non-metallic atoms necessary to complete a cyclohexene ring, n and d each represents a positive integer of from 1 to 2, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the thiazole series, those of the benzothiazole series, those of the naphthothiazole series, those of the thianaphtheno-7,6',4,5- thiazole series, those of the oxazole series, those of the benzoxazole series, those of the naphthoxazole series, those of the selenazole series, those of the benzoselenazole series, those of the naphthoselenazole series, those of the thiazoline series, those of the 2-quinoline series, those of the 4-quinoline series, those of the l-isoquinoline series, those of the 3,3-dialkylindolenine series, those of the 2-pyridine series, those of the 4-pyridine series, those of the benzirnidazole series, those of the pyrrolidine series and those of the acenaphtho[1,2]-thiazole series, provided that when Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the pyrrolidine series, R can additionally represent a monocyclic aryl group of the benzene series.

References Cited in the file of this patent UNITED STATES PATENTS 2,282,116 Brooker May 5, 1942 2,455,420 Kendall et al Dec. 7, 1948 2,697,707 Kendall et a1. Dec. 21, 1954 2,721,799 Edwards et a1 Oct. 25, 1955 2,756,227 Heseltine July 24, 1956 2,766,233 Kartinos et a1. Oct. 9, 1956 2,773,869 Leavitt Dec. 11, 1956 OTHER REFERENCES Chemical Abstracts, 16, 3101 (abstract of Brit. Med. Journal, 1922 I, 514-5).

Chemical Abstracts, 19, 530 (abstract of Proc. Roy. Soc., London, 96B, 317-33, 1924).

UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,882,158 April 14, 1959 Leslie G. S. Brooker et a1.

It is hereby certified that error appears in the printed specification of the above numbered gatent requiring correction and that the said Letters Patent should read as correcte below.

Column 2, line 9, for (e.g., pryidine read --(e.g., pyridine; column 6, line 66, Example 11, second line below the formula, for (1.15 g., 1 mol.) read (1.86 g., 1 mol.); column 10, line 34, Example 22, fourth line below the formula, for othen read -then--; column 11, line 49, for sensiitve read -sensitive-; column 12, line 36, for separated read separately; line 41, for sensitiometer read -sensi'tometer-; column 15, lines 3 to 9 inclusive, the left-hand portion of the formula should appear as shown below instead of as in the patent:

column 16, lines 5 to 8 inclusive, the formula should appear as shown below instead of as in the patent:

CN RI\'I'(:CH==CH),.-1:T3=CH(CH=CH)4-1-C/ c=c \\Q, \R, Signed and sealed this 13th day of October 1959.

Attest: KARL H. AXLINE, ROBERT C. WATSON,

Attestz'ng Oficer. Oonvmz'csioner of Patents. 

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION SENSITIZED WITH A POLYMETHINE DYE SELECTED FROM THOSE REPRESENTED BY THE FOLLOWING GENERAL FORMULA: 